I know this has been hit on before, believe me...I have been looking everywhere for an answer. I purchased a 53 Super A, already converted to a 12 volt system, old girl ran great, but was "patina" in color, wiring harness was home made, etc....so, as I always do...I go in, head first. New cloth wrapped/repo wiring harness, for 12 volt converted Super A's, new steering wheel,fixed a few leaks, painted tractor--automotive green etch, 2k primer/single stage IH-50 red, new lights, new tires, new gauges, switches, radiator fixed and hot tanked, new fan, etc. I still have the hood/grill to finish body work wise. I can NOT get her to charge. I got a reman. GM 1 wire from Autozone, and have already taken it back and via them, it "tested" fine. I have it wired, just as it says do via the diagram on this site..."other" than...could not find a stand-a-lone, "old school" idiot light(everything LED now)...so had a 11 ohm, 3-5 watt resistor around, so added that into the circuit going back from F1 at the alternator, back to the open side of the switch. F2, goes to the hot pin, on back of the alternator, which feeds back to the + side of the 60 amp new meter I installed. I have some 10 ohm, 2 watts on the way, to see if that is the issue. I changed the 2.5 inch alternator pulley, to a 2.3 inch alternator pulley. I even grounded the alternator housing, back to the alternator bracket, to see if that will help and make sure it's not a grounding issue, as I did repaint the tractor and a lot, was done "piecemeal". Have also put in a internal resisted coil...and electronic ignition..which, is the bomb, in my book...but..this charging issues is beating my brain!!! When I "first" put this new..aka "rebuilt" alternator on...on it's first crank..it went to charge for about 45 seconds...now...nothing. At full throttle, only getting some 12.7 volts, at the alternator, or battery. Alternator is spec'd for a 1970's model/ 6 cylinder GM, one wire. I understand the later(80's) 1 one wire alternators would excite on start up and at lower RPM. I have checked via screwdriver to the back of the alternator, it is magnetized. [/img]

I'm also still using the old battery that came with the tractor...it seems to hold a charge fine after putting on the charger....I have a new battery and battery box to put in, I have not tried that
yet...but...if the old battery charged will crank the tractor, I can't see how that will cause a charging issues. Fully charged, old battery would top off at around 13 volts.

"Alternator is spec'd for a 1970's model/ 6 cylinder GM, one wire. I understand the later (80's) 1 one wire alternators would excite on start up and at lower RPM."

NOT sure where you are coming from with this, but GM never used "one wire" alternators in those applications, or for that matter never made any 10SI's or 12SI's that were "one wire", at least for automotive use, AFAIK.

The "one wire" alternators are aftermarket bastardizations of the OEM alternators.

That being said, if the bearing/shaft area of the alternator is strongly magnetized ts should be charging, unless there's a stator winding or rectifier problem.

Also, you wrote:

"Alternator is spec'd for a 1970's model."

If a really early 70's it would NOT have an internal regulator, '70, '71, '72, and possibly some 1973 models did NOT have an internal regulator, although they are very similar in appearance to the internally regulated units that immediately followed.

If the two flat terminals are like THIS... I I refer to the "F" and "R" markings, (and IGNORE the "1" and "2") and it is NOT internally regulated.

If the two flat terminals are like THIS... - - refer to the "1" and "2" markings, (and IGNORE the "F" and "R") and it is NOT internally regulated.

Everything about your wiring sounds good. But you don't have a "one wire", you have a 3 wire. Anyway, sounds
like it is wired correctly.

Just to double check, be sure you have voltage at the #1 terminal with the ignition on. Should have battery
voltage to the BAT and #2 all the time.

The only thing that looks suspicious is the angle of the belt. What is driving the alternator? It appears to
be driven off something above the crank, aux off the water pump?. That may be too slow to excite. Any way to
speed it up?

The belt looked off to me too, but you said it charged for a few seconds, so it can't be low rpm. Do the voltmeter checks, actually you can use a test light here. If that's OK, just pull the alternator and take it to your friendly neighborhood parts store, they'll check it for you.

One possible answer is to just get a true one-wire alternator, attach it directly to the "load" side of the ammeter, and be done with it.

If you are determined to make this work, and you have a correct internally regulated Delco 10SI style alternator, you can completely disconnect the excite wire, and manually excite the generator by running a jumper wire to your starter switch, and manually touch it there momentarily after the tractor has started and is running at about 1/2 throttle. If it starts charging, all you need to figure out after that is where to get an LED or a diode.

You do have the BAT wire from the alternator connected to the opposite side of the ammeter from the battery, right? If you connect to the same side, it is bypassing the ammeter and won't show a charge, though it will be charging.

You say new gauges...well i just put a new chevy 3 wire alternator on my jd b and new amp gauge. I was having charging problems at first (no charge) and nothing showing on amp gauge, so for fun I switched the wires on the amp gauge and it started charging at 14ish volts. But the gauge read negative lol. I thought there's either something wrong with the gauge, or my wires weren't on the right sides.

Is the belt tight from the crank pulley to the fan? Also you can by pass the regulator by grounding the little tab in the D shaped hole in the back of the alt. Hook a jumper cable from the alt case directly to the battery ground post. & see if it will charge. You have a lot of paint that prevents good contact.

My setup. I believe I spec'd a 1973 Chevy, 6 cylinder alternator....as I had a 73, V8 Chevy pickup, as a teenager and didn't remember it having a external voltage
regulator--and I had to mechanic on it all the time-LOL! My thinking was the 6, would have a lower rpm range. I went thru the suggested checks..BAT at alternator
and #2 terminal are hot all the time/switch OFF and battery hooked up. #1 terminal was around 10.5 volts, with the switch ON, no voltage with switch off. On the
cluster, the BAT wire from the alternator goes to the - side of the amp gauge, voltage from the battery goes to the + side of the amp gauge. The "red" wire
pictured goes from the open side of the switch, thru 11 ohm resistor and also now a 12v LED light(have tried with/without LED before) and runs to terminal 2 on
the alternator. I found no resistance in the LED light, so thought I'd give that a whirl. IF I cut the switch on, amp meter moves slightly to discharge,
headlights, tail light on...moves further to discharge, with the tractor off. My Super A doesn't have a water pump, alternator is driven off the fan pulley(new,
aftermarket) and the crank turns the fan. I purchased the "kit" that included brackets to mount the alternator. Maybe I did get alternator of the wrong year. I
dropped alternator pulley size down anyway, from a 2.6 to a 2.3 overdrive pulley. We have an optical tach at work and was going to borrow to see exactly what RPM
the alt. pulley was actually turning at high/low speeds.

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